1. Field of the Invention
The present invention relates to an image taking apparatus having a magnifying function of varying a magnification ratio for an object image by a zoom lens or the like, a control method for the apparatus, and a control program for the apparatus.
2. Related Background Art
Conventionally, electronic cameras which have an image taking element such as a CCD and a zoom function of performing a magnifying operation by moving a plurality of lens units in the optical axis direction have been widely known. These cameras are roughly classified into two types: cameras which are mainly used for still image taking and cameras which are mainly used for moving image taking. The former cameras, in particular, are required to perform the above magnifying operation at a high speed at the time of startup or determination of a view angle so as not to miss the shutter chance. In addition, in general, still images are more noticeable in frame distortion and blur than moving images, and hence are required to have high image quality. This makes it necessary to position lens units with high precision.
Conventionally, in order to satisfy such requirements for still images, a driving actuator such as a DC motor and a deceleration mechanism are used for a magnifying mechanism. A high-speed driving operation is performed by driving the above motor at a high rotational speed, and positioning control is performed to stop the lens units always from one direction, thereby positioning the lens units with high precision without being affected by the backlash of the deceleration mechanism.
In the conventional camera having the above function/control, if magnifying operation is done during moving image taking, the view angle changes too quickly or shifting operation at the time of positioning becomes awkward.
According to one aspect of the invention, an image taking apparatus performs drive control to allow a zoom lens for magnifying an object image to stop at a stop position from both a telephoto side and a wide-angle side when a first mode is selected, and performs drive control to allow the zoom lens to stop at the stop position from only one of the telephoto side and the wide-angle side when the second mode is selected, thereby eliminating awkward variations in view angle.
Other aspects of the present invention will be obvious from the preferred embodiment described in detail below in conjunction with the accompanying drawings.